(576g) A Platform for Rapid Portable Analysis of Environmental Micro/Nano-Plastics

Plastic waste pollution poses significant concerns because polymeric materials rapidly degrade into micron to nanometer-sized particulate fragments. These tiny micro/nano plastic debris become easily dispersed throughout the environment where they enter the food supply and pose potentially significant health risks. But current analysis methods cannot differentiate and quantify polymeric nanoparticles (i.e., nanoplastics) in the ocean and freshwaters from other types of nanoparticles. Here we address this need by applying a microfluidic approach that enables nanoplastic particles to be characterized by size and concentration. Two laminar streams, one containing a tracer dye solution and the other containing an aqueous polymeric nanoparticle suspension, are injected in parallel through a microchannel. The dye and nanoparticles laterally diffuse across the interface between the two steams, where the resulting interfacial complexation produces a unique fluorescent signature distinct from the diffusion profile expected from either the dye or nanoparticles alone. A ratiometric analysis approach correlates the difference between the maximum and minimum of the first-order spatial derivative of fluorescent intensity to the nanoparticle surface area available for complexation with the tracer dye. We demonstrate the operation of our system using polystyrene nanoparticles in the 20 – 100 nm size range to establish the fluorescent signal’s dependence on size and concentration, and quantify sensitivity and detection limits. The choice of tracer dye can be tuned to produce fluorescent signatures that depend on nanoparticle composition, laying the groundwork for rapid field-based analysis of environmental micro/nano plastics.